Electroluminescent device and methods for its production and use

ABSTRACT

A luminescent device comprises an electroluminescent phosphor in operative contact with a light-emitting material wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material. Methods of making the device and using it in an electroluminescent display are also described.

CROSS REFERENCE TO RELATED PATENTS AND PATENT APPLICATIONS

The subject matter of the present invention is related to and claims thebenefit of copending and commonly assigned U.S. patent application Ser.No. 10/207,576, filed Jul. 29, 2002, which is relied on herein andincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to electroluminescent devices, and moreparticularly to alternating-current powered electroluminescent devices.

(2) Description of the Related Art

Luminescence is a general term that is used to describe the emission ofradiation from a solid when it is supplied with some form of energy. Thevarious types of luminescence can be distinguished by the method ofexcitation that is used to supply the energy. Electroluminescenceexcitation results from the application of an electric field, which maybe either AC or DC. Whatever the form of energy input to the luminescingmaterial, the final stage in the process is an electronic transitionbetween two energy levels. See, e.g. Display Devices, athttp/www/geocities.com/Athens/Bridge/2702/CAP4I (Oct. 28, 2002).

Fluorescence occurs when a material emits visible light after beingexcited by an excitation source applied from outside. A fluorescentlamp, a discharge tube, and a cathode ray tube utilize fluorescence. Amaterial that emits fluorescence is called a phosphor.

Electroluminescence is a solid state phenomenon, which involves theemission of visible or invisible radiation as a result of the absorptionof exciting energy. It is a general term which includes bothfluorescence and phosphorescence. Invisible light further includesinfrared and ultraviolet radiation.

An electroluminescent (EL) display device generally includes a layer ofphosphor positioned between two electrodes, with at least one of theelectrodes being light-transmissive. At least one dielectric also ispositioned between the electrodes so the EL display device functions asa capacitor. When a voltage is applied across the electrodes, thephosphor material is activated and emits light.

Phosphors may be employed in the manufacture of electroluminescentdevices. Long-lasting phosphors are known in the art, and includesulfides and oxides. Many long-lasting phosphor products are those witha sulfide as their base crystal, such as ZnS:Cu. Phosphorescencecharacteristics are influenced by composition, particle diameter, andenvironment, in particular, the phosphorescence brightness of phosphors.

Other light-emitting materials, such as certain small molecules andcertain polymers, may also be employed in the manufacture ofelectroluminescent devices. Suitable light-emitting small moleculesinclude quinolines, fluorescein, and the like.

Light-emitting polymers (LEPs) may further be employed in themanufacture of electroluminescent devices. Suitable light-emittingpolymers include MEHPPV(2-methoxy-5-2′-ethylhexyloxy)-1,4-phenylenevinylene copolymer,MEH-BP-PPV(poly[2-Methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene]),and MEH-CN-PPV(poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene). TheseLEPs absorb radiation at about 400 to about 500 nm (blue light) and emitradiation at about 600 and 800 nm (yellow, orange, and red light).

The short lifetime of organic light-emitting polymers (LEPs) has been amajor impediment to their use in commercial environments. Organic LEPsare unstable when exposed to air and humidity. In addition to oxygen,other contaminants present in air, such as ozone and NH₃, also adverselyaffect the useful lifetime of LEPs.

Heretofore, lamps fabricated from LEPs have been entirely encapsulated,or have had exposed surfaces coated with protective layers to achievestability. This large-scale encapsulation/coating process is costly, andrequires the use of a relatively expensive transparent material.

Another characteristic of phosphor materials is that the selection ofwavelengths of emissive radiation that could be obtained from phosphorsthat were excitable by a simple electric field was substantially limitedto blues, greens and oranges—depending upon the dopant that was used inthe phosphor. Radiation of other wavelengths could be obtained fromdifferent phosphors, but those phosphors required high-energy photons oran electron beam for excitation. Accordingly, effective provision ofelectroluminescent radiation having wavelength of a desiredspectra—other than blue, green or orange—was difficult to achieve.

It would be useful, therefore, to provide an electroluminescent devicecapable of emitting radiation at a desired wavelength that was otherthan blue, green, or orange, but which was powered by an electric field.It would also be useful if the electric field could be supplied by analternating current source. Furthermore, it would be useful if theelectroluminescent device could be produced simply and easily, andwithout the use of inert atmospheres, high vacuum, sputtering, or theuse of electrodes composed of low-work function metals, such as calcium,aluminum, sodium and magnesium, or their oxides.

SUMMARY OF THE INVENTION

Briefly, therefore the present invention is directed to a novelluminescent device comprising an electroluminescent phosphor inoperative contact with a light-emitting material wherein excitation ofthe electroluminescent phosphor by an alternating current electricalfield causes the emission of light by the light-emitting material.

The present invention is also directed to a novel method of making anelectroluminescent device comprising the steps: placing a phosphor andan insulating layer between a first electrode and a second electrode;and placing a light-emitting material in operative contact with thephosphor.

The present invention is also directed to a novel electroluminescentdisplay comprising an electroluminescent phosphor in operative contactwith a light-emitting material wherein excitation of theelectroluminescent phosphor by an alternating current electrical fieldcauses the emission of light by the light-emitting material; and a firstelectrode and a second electrode, between which is located theelectroluminescent phosphor and an insulating layer.

Among the several advantages found to be achieved by the presentinvention, therefore, may be noted the provision of anelectroluminescent device capable of emitting radiation at desiredwavelengths that are in addition to blue, green, or orange, but which ispowered by an electric field; the provision of an electroluminescentdevice where the electric field can be supplied by an alternatingcurrent source; and the provision of an electroluminescent device whichcan be produced simply and easily, and without the use of inertatmospheres, high vacuum, sputtering, or the use of electrodes composedof low-work function metals, such as calcium, aluminum, sodium andmagnesium, or their oxides.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an electroluminescent device having asubstrate, a first electrode, a phosphor layer, a layer of alight-emitting material, and a second electrode;

FIG. 2 is an illustration of an electroluminescent device having asubstrate, a first electrode, phosphor particles dispersed in a layer ofa light-emitting material, and a second electrode;

FIG. 3 is an illustration of an electroluminescent device having asubstrate, a first electrode, phosphor particles and particles of alight-emitting material embedded in a dielectric and a second electrode;

FIG. 4 is an illustration of a phosphor particle coated with alight-emitting material to make a light-emitting particle;

FIG. 5 is an illustration of an electroluminescent device having asubstrate, a first electrode, light-emitting particles dispersed in adielectric, and a second electrode;

FIG. 6 is an illustration of an electroluminescent device having asubstrate, a first electrode, a dielectric layer, a layer composed oflight-emitting particles dispersed in a dielectric, and a secondelectrode;

FIG. 7 is an illustration of an electroluminescent device having asubstrate, a first electrode, a dielectric layer, a layer composed ofphosphor particles dispersed in a dielectric, a second electrode, alayer composed of a light-emitting material, and a protective layer;

FIG. 8 is an illustration of an electroluminescent device having asubstrate, a first electrode, a light-emitting layer composed oflight-emitting particles dispersed in a dielectric, a second electrode,and a front outlining electrode;

FIG. 9 is an illustration of electroluminescent device having asubstrate, a first electrode, a dielectric layer, a light-emitting layercomposed of light-emitting particles dispersed in a dielectric, a secondelectrode, and a front outlining electrode; and

FIG. 10 is an illustration of an edge view (a) and an oblique view (b)of an electroluminescent display showing a first and a second electricallead connecting a source of alternating current to the first electrodeand the second electrode, respectively, of an electroluminescent deviceof the present invention, and with the oblique view showing anilluminated element in the form of a letter “A”.

Corresponding reference characters indicate corresponding part thoughtthe several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, it has been discovered that aluminescent device can be constructed that comprises anelectroluminescent phosphor in operative contact with a light-emittingmaterial, wherein excitation of the electroluminescent material by analternating current electrical field causes the emission of light by thelight-emitting material. In one embodiment, an electrode, which can becomposed of poly(3,4-ethylenedioxythiophene) (PEDOT), for example, canbe applied to a substrate, such as a plastic film, or a fabric.Particles of a phosphor, such as copper-doped zinc sulfide (ZnS:Cu), canbe coated with a light-emitting material, such aspoly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV), andthe coated particles can be compounded with a binder polymer into aUV-curable ink. The ink easily can be applied to the electrode-coatedsubstrate to form a light-emitting layer by conventional methods such asscreen-printing, or ink-jet printing, for example. The cured ink layeracts as an electrically insulating layer that contains the coatedphosphor particles. A second electrode, which can be transparent to theradiation emitted by the light-emitting material, and which can also becomposed of poly(3,4-ethylenedioxythiophene), is then applied over thecured ink layer. If desired, layers of dielectric materials can be addedbetween the electrodes, or protective layers can be used to coat thedisplay. Application of an AC electrical field across the two electrodescauses excitation of the electroluminescent phosphor, which, in turn,transfers energy to the light-emitting material, which emits radiationfrom the device.

The novel device has a number of advantageous features that include theability to provide luminescent light of a desired frequency by supplyingonly an AC electric field. In other words, the device provides a way toexcite luminescent materials that emit radiant energy at a desiredwavelength, but which are not normally excitable by an electric field.Heretofore, electroluminescent materials, such as ZnS:Cu, ZnS:Mn, orZnS:Ag, or the like, have provided a limited choice as to the colors oflight emitted. If other colors are required, one had to resort tomaterials that required methods of excitation other than a simple ACelectric field. Such methods included photoexcitation by laser,collimated light, etc., or cathodoexcitation, by bombardment with a beamof electrons. Now it has been discovered that by judicious selection ofmaterials, initial excitation of an electroluminescent phosphor can beobtained by imposing an AC field, and radiant energy of almost anydesired wavelength—from UV, to visible, to IR—can be produced. This hasbeen achieved by coupling the phosphor with a separate light-emittingmaterial. In an alternative embodiment, the device can employ one ormore intermediate energy-transfer materials that transfer energy betweenthe electroluminescent phosphor and the light-emitting material. Eachintermediate layer, in turn, being excited by a luminescent materialthat is either emitting radiant energy of a particular wavelength ortransferring energy by another mechanism, and then radiating energyitself at a wavelength that excites a separate luminescent material. Thecombination of luminescent materials forms a cascade of energy transfer,starting with excitation with an AC electric field and ending withemission of radiant energy of a desired wavelength by a light-emittingmaterial.

An additional advantage of the present device is that is it easilyfabricated by inexpensive and conventional means, such as, for example,screen printing, ink jet printing, or the like. The devices require nolow-work function electrode materials, such as calcium, aluminum,sodium, or magnesium, or the oxides thereof, and, therefore, are lesssusceptible to corrosion than conventional devices that include thesemetals. Moreover, the present devices do not require expensivefabrication techniques such as vacuum fabrication, vapor deposition, orsputtering. Fabrication of the present devices can occur entirely atambient conditions and without the provision of special atmospheres.

Furthermore, due to the structure and the materials that can be used inthe present devices, there is no need to encase the devices in glass toprotect their stability. Such simple fabrication techniques result inelectroluminescent devices having a greater range of colors, which canbe produced at lower cost, and which can be applied over larger areas byconventional printing techniques.

One element of the present device is an electroluminescent phosphor. Anysolid material that is electroluminescent—that is, can emit radiationafter excitation by an alternating current (AC) electrical field—canserve as the electroluminescent phosphor of the present invention. Inthe present invention, the electroluminescent phosphor is capable ofemitting radiation at a first wavelength.

As used herein, the terms “radiation” and “light” can be usedinterchangeably, and include ultraviolet, visible, and infraredradiation.

As used herein, when it is said that a material emits light at aparticular wavelength, it should be understood that some luminescentmaterials can emit light at several different wavelengths, and what ismeant is the principle or peak wavelength of the radiation emitted bythe material. The wavelength of radiation can also be referred to interms of its frequency, and each of the two terms would be recognized bya skilled artisan as being related to the other and interconvertable.

Electroluminescent phosphor materials can be inorganic solids or organicmaterials. Inorganic solid phosphors are preferred.

Examples of electroluminescent phosphors that are useful in the presentinvention include CdSe; InAs; LaPO₄, undoped or doped with one or moreof Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; ZnS, undoped, ordoped with Ag, Cu, Mn, Tb, TbF, TbF₃; ZnSe, undoped or doped with Cu orMn; undoped or doped ZnCdS; compounds that can be expressed as M^(IIA)M₂^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba and M^(III)=Al, Ga, In, or Y,undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures of any two or more ofthese materials. When a phosphor is doped with a material, the dopedphosphor can be expressed as: (the name of the phosphor molecule:thedopant). By way of example, copper-doped zinc sulfide can be expressedas ZnS:Cu.

Commercially available phosphors, such as, for example, phosphors “830”,“TNE”, and “GGS” (all available from Sylvania Co.) are suitable for usein the present invention.

Any of the electroluminescent phosphor materials that are described insuch publications as: (1) Phosphor Handbook, Shionoya, S. and W. M. Yen,Eds. CRC Press, Boca Raton, Fla. (1999); (2) Hebbink, G. A., et al.,Adv. Mater, 14(16):1147-1150 (2002); (3) Gumlich, H.-E. et al.,Electroluminescence, Chap. 6, pp. 221-269, in Luminescence of Solids, D.R. Vij, Ed., Plenum Press, New York, (1998); (4) Suyver, J. F. et al.,Photochemistry of layers of ZnS:Mn2+ nanocrystals, in Proceedings of the2^(nd) International Symposium on Advanced Luminescent Materials andQuantum Confinement, 201^(st) Meeting of the Electrochemical Society,175 (2002); and (4) in other publications by Suyver, listed athttp://www.phys.uu.nl/˜suyver/Publications (Nov. 27, 2002), can be usedas the electroluminescent phosphor of the present invention. Additionalinformation about useful phosphors and methods of preparingelectroluminescent phosphor materials can be found in U.S. Pat. Nos.5,598,058, 5,602,445, 5,711,898, 5,702,643, 5,700,592, 5,700,591,5,677,594, 5,675,217, 5,643,496, 5,635,110, 5,612,591, 5,598,059,5,593,782, 5,554,449, 5,543,237, 5,309,071, and 5,309,070.

Some inorganic electroluminescent phosphors can be purchasedcommercially from such sources as Phosphor Technology, Ltd., Essex,England; South Bank University, London, England; and Osram Sylvania,Danvers, Mass.; among others.

The electroluminescent phosphor can be used in the present device in anyphysical form, but it is preferred that the phosphor is a solidmaterial. The phosphor can have any physical shape, but particles arepreferred. The particles can be roughly spherical, or they can beirregular. The particles can be of any size. It is preferred, however,that the particles are sufficiently large to preserve the crystallinefine structure necessary for luminescent activity. When the size of aphosphor particle is described herein, it should be understood that itis the nominal size (average diameter of a roughly spherical particle)that is being described. Accordingly, the terms “10 micron particles”would be interpreted to be a number of roughly spherical solid particleshaving a number average diameter of 10 microns.

In an embodiment of the present device, the phosphor particles have anaverage nominal size of from about 0.05 microns to about 50 microns, andpreferably, have an average nominal size of from about 10 microns toabout 40 microns. When it is desirable to use the particle size of thephosphor particles as a parameter for controlling the wavelength of theradiation emitted from the phosphor, the preferred size range of theparticles is from about 0.1 to about 10 nm, and more preferably, fromabout 0.5 nm to about 5 nm, and yet more preferably, from about 1 nm toabout 3 nm.

Some commercially produced electroluminescent phosphor particles arecoated with a protective coating of, for example, aluminum nitride, orsilicon oxide. The particles can be used in the present inventionwhether or not such coatings are present.

In the present device, the electroluminescent phosphor is in operablecontact with a light-emitting material. The light-emitting material ofthe present device can be any material which is excited when inoperative contact with the excited electroluminescent phosphor and whichis capable of emitting light of a wavelength that is different than thelight emitted by the electroluminescent phosphor.

In an embodiment of the present invention, the light-emitting materialis an inorganic solid. Examples of such materials include LaPO₄, undopedor doped with one or more of Pr, Nd, Er, or Yb (See, e.g., thedescription of such near IR-emitting materials by Hebbink, G. A., etal., in Adv. Mater, 14(16):1147-1150 (2002)). YOS, undoped or doped withEr. Inorganic light emitting materials can also include compounds havingthe description: M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba,and M^(III)=Al, Ga, In, Y, or is optionally absent, and the compoundscan be undoped, or doped with Eu²⁺ or Ce³⁺. Mixtures of such materialscan also be used.

In a preferred embodiment of the present invention, the light-emittingmaterial is an organic material. Examples of organic materials that areuseful as the light-emitting material in the present device include:antracene, undoped or doped with tetracene; aluminumtris(8-hydroxyquinolinate); poly-(p-phenylenevinylene) (PPV);poly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV);poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene](MEH-BP-PPV),poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene(MEH-CN-PPV),poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-1,2-ethylene-1,4-phenylene](DiSiPV); Tb tris(acetylacetonate);Eu(1,10-phenanthroline)-tris(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate;Eu tris(dibenzoylmethanato)phenanthroline; Tbtris(acetylacetonate)phenthroline; Eu(4,7-diphenylphenanthroline)-tris(4,4,4-trifluoro)-1-(2-thienyl)-butane-1,3-dionate;Nd(4,7-diphenylphenanthroline)(dibenzoylmethanato)₃;Eu(dibenzolmethanato)₃-2-(2-pyridyl)benzimidazole;Eu(dibenzolmethanato)₂-1-ethyl-2-(2-pyridyl)benzimidazole;Tb-[3-(5-phenyl-1,3,4-oxadiazol-2-yl)-2,4-pentanedionate]₃;lanthanide-tris(4-methylbenzoate); lanthanide-tris(4-methoxybenzoate);Tb-tris(4-methylbenzoate); Tb tris(4-methoxybenzoylbenzoate); Eutris(4-methoxybenzoylbenzoate);Tb-tris(tetradecylphethalate)phenantroline; Tb-imidodiphosphinate; Tb1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one; polypyridine;poly(p-phenylenevinylene);poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene];poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene];poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene)-alt-co-(4,4′-biphenylene-vinylene)];poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene)];poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(4,4′-biphenylene)];poly[{9,9-dioctyl-2,7-divinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene}];poly[{9,9-dioctyl-2,7-bis(2-cyanovinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}];poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylenephenylene)];poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene}-alt-co-{2,5-bis(N,N′-diphenylamino)-1,4-phenylene}];poly[{9-ethyl-3,6-bis(2-cyanovinylene)carbazolylene)}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}];poly[(9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di-(p-butylphenyl)-1,4-diaminobenzene];poly[2-(6-cyano-6-methylheptyloxy)-1,4-phenylene);poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}];poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}];poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-ethylenylbenzene)];poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)];poly[(9,9-dihexylfluorenyl-2,7-divinylenefluorenylene)];poly[(9,9-dihexyl-2,7-(2-cyanodivinylene)-fluorenylene)];poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)];poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)];poly(9,9-dioctylfluorenyl-2,7-diyl; poly(9,9-dihexylfluorenyl-2,7-diyl);poly[9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl];poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di(p-butyloxyphenyl)-1,4-diaminobenzene)];poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-diphenyl)-N,N′-di(p-butyloxy-phenyl)-1,4-diaminobenzene)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,10-anthracene)];poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-bis{4-butylphenyl}-benzidine-N,N′-{1,4-diphenylene})];poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(2-methoxy-5-{2-ethylhexyloxy}-1,4-phenylene)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9′-spirobifluorene-2,7-diyl];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(2,5-p-xylene)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(3,5-pyridine)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-phenylene)];poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9-di-{5-pentanyl}-fluorenyl-2′,7′-diyl;poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′{2,2′-bipyridine})];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′-{2,2′:6′,2″-terpyridine})];poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N′bis{p-butylphenyl}-1,4-diaminophenylene)]; 8-hydroxyquinoline; fluorescein; rhodamine; xanthene,substituted or unsubstituted; substituted coumarin; substitutedhydroxycoumarin; substituted or unsubstituted tetra-cyanoquinolines;ethidium bromide; propidium iodide; benzoxanthene yellow; bixbenzimide((2′-[4-hydroxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol);(2′-[4-ethoxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol));4,6-diamidino-2-phenylindole (DAPI); lithiumtetra(2-methyl-8-hydroxyquinolinato)boron;bis(8-hydroxyquinolinato)zinc;tris(benzoylacetonato)mono(phenanthroline)europium(III);tris(2-phenylpyridine)iridium(III); andtris(8-hydroxyquinolinato)gallium(III);tris(8-hydroxyquinolato)aluminum;tetra(2-methyl-8-hydroxyquinolato)boron; lithium salt;4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl;9,10-di[(9-ethyl-3-carbazoyl)-vinylenyl)]-anthracene;4,4′-bis(diphenylvinylenyl)-biphenyl;1,4-bis(9-ethyl-3-carbazovinylene)-2-methoxy-5-(2-ethylhexyloxy)benzene;tris(benzoylacetonato)mono(phenanthroline)europium(III);tris(dibenzoylmethane)mono(phenanthroline)europium(III);tris(dibenzoylmethane)mono(5-aminophenanthroline)europium(III);tris(dinapthoylmethane)mono(phenanthroline)europium(III);tris(biphenoylmethane)mono(phenanthroline)europium(III);tris(dibenzoylmethane)mono(4,7-diphenylphenanthroline)europium(III);tris(dibenzoylmethane)mono(4,7-dimethyl-phenanthroline)europium(III);tris(dibenzoylmethane)mono(4,7-dihydroxy-phenanthroline)europium(III);tris(dibenzoylmethane)mono(4,7-dihydroxyloxy-phenanthroline)europium(III);lithium tetra(8-hydroxyquinolinato)boron;4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl;bis(8-hydroxyquinolinato)zinc; bis(2-methyl-8-hydroxyquinolinato)zinc;iridium(III) tris(2-phenylpyridine); tris(8-hydroxyquinoline)aluminum;andtris[1-phenyl-3-methyl-4-(2,2-dimethylpropan-1-oyl)-pyrazolin-5-one]-terbium.Mixtures of two or more of any of these organic light-emitting materialscan also be used.

The light-emitting material of the present invention may be synthesized,or may be purchased from commercial suppliers, one of which is AmericanDye Source, Quebec, Canada, Further information on the synthesis and useof lanthanide complexes can be found in Kido, J. et al., Chem. Rev.102:2357-2368 (2002). Further information on organic light emittingmaterials that emit in the infrared region, which are useful in thepresent invention, can be found in U.S. Patent PublicationUS2001/0030325 A1.

In an embodiment of the present invention the light-emitting material isone that is not excited by an alternating current electrical field.

In the present device, the electroluminescent phosphor is in operativecontact with the light-emitting material. By the terms “operativecontact”, what is meant is that the position in the device of theelectroluminescent phosphor relative to the light-emitting material issuch that a transfer of energy from the excited phosphor to thelight-emitting material is possible that is sufficient to raise thelight-emitting material to an excited state that results in the emissionof radiation from the light-emitting material. In one embodiment,operative contact is direct physical contact between the phosphor andthe light-emitting material. In an alternative embodiment, operativecontact is close proximity of the phosphor to the light-emittingmaterial when both are in the same layer. In another embodiment,operative contact is the presence of the phosphor in one layer and thepresence of the light-emitting material in another layer of the devicewhere the two layers are adjacent, or are separated only by a layer orlayers that permit the energy transfer from the phosphor to thelight-emitting material.

A useful feature of the present device is that it can be produced byconventional fabrication methods that do not require unusual techniquesor atmospheres. With reference to the figures that are attached hereto,one embodiment of the electroluminescent device (101) can be constructedas shown in FIG. 1, by applying a first electrode (201) to a substrate(501). Almost any material to which an electrode can be applied can beused as the substrate in the present device. An advantageous feature ofthe present invention is that the substrate can be a flexible material,such as a plastic film or a woven or non-woven textile material. It ispreferred that the substrate is an electrically insulating material.However, the substrate may be a metal, which could serve as oneelectrode.

The first electrode (201) is an electrically conductive material. It ispreferred that the first electrode is composed of a material that can beapplied to the substrate by conventional coating or printing methods,such as by screen printing, ink jet printing, or the like. In someembodiments, it is preferred that the first electrode is free of metalsand metal oxides. As used herein when describing electrodes, the term“metals” is to be understood to include high work function metals, suchas indium and titanium, as well as lower work function metals, such ascalcium, aluminum, and magnesium.

In preferred embodiments, the first electrode (201) is composed of anintrinsically conductive polymer (ICP). The terms “intrinsicallyconductive polymer”, or “ICP”, as used herein, are intended to includeany polymer that, in at least one valence state, has an electricalconductivity greater than about 10⁻⁸ S/cm and preferably greater thanabout 10⁻⁶ S/cm. ICP's generally have polyconjugated .pi. electronsystems and can be doped with an ionic dopant species to an electricallyconductive state. A number of conjugated organic polymers that aresuitable for this purpose are known in the art and include, for example,polyaniline, polyacetylene, poly-p-phenylene, poly-m-phenylene,polyphenylene sulfide, polypyrrole, polythiophene, polycarbazole and thelike, which can be substituted or unsubstituted. Such ICP's are wellknown and those of ordinary skill in the art will readily recognizethose ICP's that are within the scope of this invention.

In preferred embodiments, the first electrode is constructed ofpoly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonic acid(PEDOT/PSSA, available from Agfa-Gevaert, Mortsel, Belgium). PEDOT/PSSAis a water soluble polymer and can be applied to the substrate in theform of an aqueous solution. The aqueous solution of PEDOT/PSSA can beapplied to the substrate by any conventional technique, including, forexample, rolling, brushing, spraying, dipping, spin-coating, screenprinting, jet printing, and the like.

An electroluminescent phosphor (301) can be applied over the firstelectrode (201). Any one of the electroluminescent phosphor materialsdescribed above can be used.

A light-emitting material (401) can then be applied over theelectroluminescent phosphor.

Finally, a second electrode (202) can be applied over the light-emittingmaterial (401). The second electrode (202) can be any material that issuitable for use as an electrode. Intrinsically conductive polymers arepreferred for use as the second electrode. It is preferred that thesecond electrode is constructed of a material that is transparent to theradiation emitted by the light-emitting material in order for thatradiation to exit the electroluminescent device (101). In preferredembodiments, the second electrode is free of a metal or metal oxide. Inmore preferred embodiments, the second electrode (202) is constructed ofthe same material as the first electrode (201). One example of amaterial that is preferred for use in both the first electrode (201) andthe second electrode (202) is poly(3,4-ethylenedioxythiophene) (PEDOT).The PEDOT can be doped with polystyrenesulfonic acid (PSSA).

In an alternate embodiment, shown in FIG. 2, the electroluminescentdevice (101) can be constructed as described above, except that theelectroluminescent phosphor (301) can be present in the form ofparticles, and the particles can be embedded within, or distributedwithin, the light-emitting material (401), which can act as a matrix forthe electroluminescent phosphor particles.

In the embodiments of the device shown in both FIG. 1 and FIG. 2 it ispreferred that the layers that include the electroluminescent phosphor(301) and light-emitting material (401), of the device of FIG. 1, andthe layer containing the electroluminescent phosphor (301) andlight-emitting material (401), of the device of FIG. 2, (i.e., thelayers between the first and the second electrodes), be electricallynon-conductive. This is believed to facilitate the establishment of anelectrical field across the two electrodes when an alternating current(AC) is charged to the electrodes.

In an alternative embodiment, shown in FIG. 3, both theelectroluminescent phosphor (301) and the light-emitting material (401)can be in particulate form and both can be dispersed within a binder(601). In this case, the binder is preferably an electricallynon-conducting material. In the embodiment shown in FIG. 3, thelight-emitting material (401) can be present either as very smallparticles distributed through the binder material (601), or evendissolved in the binder material.

It should be understood that the depiction of particles in any of thedrawings is not meant to limit or represent the size or shape of anyparticle, or the relative size or shape of any particle with respect toanother type of particle.

Suitable binder materials can be any suitable thermoplastic, includingpoly(vinylbutyral), poly(vinylalcohol), poly(vinylchloride),polycarbonate, polystyrene, poly(vinylidene chloride), poly(vinylidenefluoride), poly(vinylidenedifluoride), poly(acrylonitrile),poly(oxyethylene), cellulose esters, cellulose ethers, nylon 6,6, nylon12, nylon 6,12, poly(ethylene oxide), poly(ethylene-co-vinylacetate),poly(vinylcarbazole), poly(caprolactone), polysulfone,poly(vinylpyrrolidone), poly(4-vinylphenol),poly(methyloctadecylsiloxane), and the like. A preferred binder ispoly(vinylidenedifluoride) (PVDF).

Other binder systems that may be employed include systems employingthermosetting resins, for example, systems with urethane and epoxies, aswell as UV-curable binder systems.

The binder polymer can be put into solution with, or dispersed into, asolvent. Light-emitting particles (103), binder polymer, and solvent canbe formulated into an ink, which can be applied by any conventionalprinting process. In preferred embodiments, the binder polymer andsolvent are selected so that the light-emitting material is insoluble,or has limited solubility, in the binder/solvent. By the term“insoluble”, it is meant that the light-emitting material has asolubility of less than about 10 mg/l at room temperature. It ispreferred that the light-emitting material has a solubility in thebinder/solvent system of less than about 1 mg/l. When it is said thatthe light-emitting material has limited solubility in the binder/solventsystem, what is meant is that the light-emitting material is soluble inthe binder/solvent system at room temperature of less than about 0.5% byweight. It is preferred that a light-emitting material having limitedsolubility is soluble in the binder/solvent system at room temperatureof less than about 0.1% by weight

One preferred embodiment is the dispersal of MEHPPV-coated ZnS:Cuphophor particles into poly(methylmethacrylate) orpoly(butylmethacrylate) in a suitable solvent. Some examples of suitablesolvents include tetrahydrofuran (THF), xylene, terpinol mixed isomers(TERP), ethyldiglycol acetate (EDGA), dichloroethane (DCE), and thelike, and mixtures thereof.

A preferred binder system includes a UV-curable polymer-forming systemin a liquid that can be applied by a conventional printing system, suchas, for example, a screen-printing system. An example of such apreferred binder is the ink that includes a UV curable urethaneacrylate/acrylate monomer blend of proprietary composition, designatedFD 3007 CL, available from Allied Photochemical Inc., Kimball, Mich.This type of ink can be applied by screen printing and cured by exposureto UV illumination.

Another example of a UV-curable binder system that is useful isavailable from DuPont, Wilmington, Del., and is identified as ProductNumber 5018A.

For the description of other UV curable binder systems that are usefulin the present invention, see http://www.sartomer.com/wpapers/3300.

In another embodiment, the light-emitting material (401) can be indirect contact with the electroluminescent phosphor (301). In apreferred embodiment, shown in FIG. 4, the electroluminescent phosphor(301) is coated with the light-emitting material (401), to form alight-emitting particle (103). As discussed above, the light-emittingparticle (103) can optionally have a thin coating of a protectivematerial, such as aluminum nitride or silicon oxide, between thephosphor particle (301) and the light-emitting material coating (401).

The light emitting particles (103) can be used in an embodiment of thepresent device, an example of which is shown in FIG. 5. In thisembodiment, a first electrode (201) is applied to a substrate (501), asdescribed above. A layer comprising the light-emitting particles (103)distributed in a binder (601) is then applied over the first electrode.The layer containing the binder (601) and the light-emitting particles(103) can be referred to as the light emitting layer. Next, a secondelectrode (202) is applied to the cured binder/light-emitting particlelayer.

In an optional embodiment, shown in FIG. 6, a layer of a dielectricmaterial (701), such as, for example, barium titanate, can be used inthe device. A preferred location for the dielectric layer (701) isbetween the first electrode (201) and the light-emitting layer. Anadvantage of the use of a dielectric layer at this location is that itfacilitates the formation of a suitable electric field across the lightemitting layer upon the application of an AC current across the twoelectrodes. Such dielectric layer can also be added to theconfigurations of the device shown in FIG. 1, FIG. 2, and FIG. 3, withthe same advantageous effect.

In FIG. 7, an alternative embodiment of the electroluminescent device(101) is constructed by the application of a first electrode (201) ontoa substrate (501) as described above. A layer of dielectric material(701) may be applied over the first electrode, and the dielectric layercan be followed by the application of a binder layer (601) in whichphosphor particles (301) are embedded. The binder/phosphor layer can betopped with a second electrode (202), which is preferably composed of amaterial that is transparent to the radiant energy emitted by thephosphor (301). A layer containing a light-emitting material (401) canbe applied over the second electrode, and this can be covered with aprotective layer (801), which can be a protective polymer, glass, or thelike. It is noteworthy that in this embodiment, the phosphor and thelight-emitting material are separated by the second electrode.

FIG. 8 is an illustration of an electroluminescent device having asubstrate(501), a first electrode (201), a light-emitting layer (105)composed of light-emitting particles (103) dispersed in a dielectric(601), a second electrode (202), and a front outlining electrode (903).

FIG. 9 is an illustration of electroluminescent device having asubstrate (501), a first electrode (201), a dielectric layer (701), alight-emitting layer (105) composed of light-emitting particles (103)dispersed in a dielectric (601), a second electrode (202), and a frontoutlining electrode (903).

FIGS. 10( a) and (b) illustrate the use of any one of theelectroluminescent devices of FIGS. 1, 2, 3, 5, 6, 7 or 8 in analternating current electrical system. Here, a first lead (901) of theAC circuit is connected to the first electrode (201), and a second lead(902) is connected to the second electrode (202). The leads can be madeof any material that will conduct an electric current, but the use of ametal, such as silver, is preferred. The use of the device to display aspecific illuminated area, here the letter “A”, is illustrated in FIG.10( b).

When a source of alternating current of the proper voltage and amperageis applied to the first lead (901) and the second lead (902), theresulting electric field causes excitation of the phosphor (301), which,in turn, causes excitation of the light-emitting material (401), whichemits radiation from the device.

If desirable, other system components, such as timing devices, switches,and the like can be added to the electrical system to control theoperation of the electroluminescent device. By way of example, thedevice can be made to turn on and off, to blink, to fade and/orbrighten, and the like.

When the present electroluminescent device is produced, certain relativeamounts of the phosphor (301), the light-emitting material (401), andthe binder (601)—when a binder is used—have been found to be useful. Ithas been found that a preferred ratio of the amount by weight of thelight-emitting material (401) to the weight of the phosphor (301) iswithin a range of from about 1×10⁻⁶:1 to about 1:1, more preferred is aratio of from about 0.00001:1 to about 0.5:1, even more preferred is aratio of from about 0.0001:1 to about 0.3:1, yet more preferred is aratio of from about 0.0005:1 to about 0.1:1, and even more preferred isa ratio of from about 0.0005:1 to about 0.01:1.

When a binder is used, it is preferred that the ratio of the sum of theamount by weight of the phosphor (301) and the amount by weight of thelight emitting material (401) to the amount by weight of the bindersolids is within a range of from about 1:1 to about 50:1, more preferredto be within a range of from about 6:1 to about 30:1, and yet morepreferred to be within a range of from about 4:1 to about 10:1.

The electroluminescent device of the present invention can be used insigns, displays, and, in fact, anywhere a conventionalelectroluminescent system is useful.

The following examples describe preferred embodiments of the invention.Other embodiments within the scope of the claims herein will be apparentto one skilled in the art from consideration of the specification orpractice of the invention as disclosed herein. It is intended that thespecification, together with the examples, be considered to be exemplaryonly, with the scope and spirit of the invention being indicated by theclaims which follow the examples. In the examples all percentages aregiven on a weight basis unless otherwise indicated.

EXAMPLE 1

This example illustrates the production of an electroluminescentphosphor particle coated with a light-emitting material.

Particles of an electroluminescent phosphor, such as ZnS:Cu are preparedby precipitation, spray pyrolysis, spray chilling, and the like. Furtherreduction in particle size may be achieved by micronizing using an airmill or grinding them to an ultimate particle size of approximately 50microns or less.

Phosphor particles of the desired size are then coated with alight-emitting material, such as poly(p-phenylene vinylene) orpoly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene]. In thisprocess, the phosphor particles are fluidized in an air or nitrogenstream and the light-emitting material is spray coated onto theparticles to form encapsulated particles (Light-Emitting Particles). Inan alternative method, the light-emitting polymer can be dispersed orput into solution in a solvent. The light-emitting polymer solution isthen added to the phosphor particles with mixing. When the particles arecoated with the light-emitting polymer/solvent mixture, the solvent canbe removed by evaporation, such as in a rotating/vacuum device whilegentle heat is being applied.

If desired, a printing ink may be formulated by mixing the encapsulatedphosphor particles with one or more binder polymers, such as, forexample, poly(methylmethacrylate) or poly(butylmethacrylate), in asuitable solvent. The ink is then ready for storage or for applicationto form a part of an electroluminescent device.

EXAMPLE 2

This illustrates the fabrication and testing of of electroluminescentdevices that incorporate light-emitting particles composed of variousphosphor/light-emitting material combinations.

With gentle heating as needed, one gram of polymethylmethacrylate(PMMA), polystyrene (PS), or poly(vinylidenedifluoride) (PVDF) wasdissolved in 10 grams of 1,2 dichloroethane (DCE), tetrahydrofuran(THF), xylene, terpinol mixed isomers (TERP), ethyldiglycol acetate(EDGA), or mixtures of two or more of these, in a 25 ml glass vial. In aseparate 15 ml glass vial, 0.2 gm of particles of either TNE “white”, orGGS “white” type phosphors, available from Sylvania Corporation, weremixed with 0.5 gm of MEHPPV. After the particles and the polymer werewell mixed, 0.5 gm of the PMMA/DCE polymer carrier solution describedabove was added to the vial, and the contents were mixed and heated to60° C. for one minute. The light-emitting material coated phosphorparticles in the PMMA binder

The amount of the phosphor particles, the binder, the MEHPPV, and thesolvents were varied from the amounts described above in order todetermine the effect of the relative amounts of each component.Combinations of phosphor, light-emitting material, binder, bindersolvent, and relative amounts of these materials were used as shown inTable 1.

Electroluminescent devices of the general type shown in FIG. 5 wereconstructed by screen printing (through a polyester screen of 158 mesh)a first electrode (201) of PEDOT onto a sheet of polycarbonate (0.030″thick) used as the substrate (501). The PEDOT was cured at 220° F. Next,a layer of Allied UV curable ink, product number FD 3007 CL, availablefrom Allied Photochemical, Inc., Kimball, Mich., was screen printedthrough a patterned 158 mesh screen onto the first electrode, but a 2 mmdiameter well was left unprinted. One microliter of the mixturecontaining the light-emitting material-coated phosphor particles in thebinder was added to the well and the binder was cured by heating to forma light emitting layer. When the light emitting layer was cured, asecond electrode (202) of PEDOT was screen printed over the dielectriclayer and the light-emitting layer well, and the PEDOT was cured asdescribed above. Electrode leads of silver were screen printed tocontact each PEDOT electrode. Each of the electroluminescent devices wasconnected to an AC source of controlled voltage and the devices weretested to determine (1) the minimum voltage (at 400 Hz) at which lightwas first emitted, (2) the intensity of emitted radiation at standardconditions of 340 v, 400 Hz., and (3) the color of the emittedradiation.

TABLE 1 Components and performance of electroluminescent devices.MEHPPV + MEHPPV/ phosphor/ Phosphor Binder Characterization of lightemission^(f) MEHPPV ratio Binder Binder ratio Freq. Power IntensityColor No. Phosphor^(a) Conc.^(b,c) (wt/wt) Binder^(d) Solvent^(e) Conc'n(wt/wt) (kHz) (volts) (NITS) x y OA TNE   1% 0.01:1 None None  0infinite 0.4 61  FLE^(g) n/a n/a 0.4 340 1.63 n/a n/a 2 340 4.43 n/a na5 340 6.6 n/a n/a 10 340 6.83 n/a n/a 15 340 6.52 n/a n/a 20 340 6.69n/a n/a  1 830  0.1% 0.001:1 PMMA Acetonitrile 20% 5:1 0.4 340 No lightemission  2 830  0.5% 0.005:1 PVS MeOH 20% 5:1 0.4 74 FLE n/a n/a 0.4340 0.95 0.463 0.378 2 340 2.38 0.439 0.346 5 340 3.34 0.418 0.324 10340 4.18 0.406 0.301 15 340 3.95 0.390 0.289 20 340 3.33 0.385 0.286  3830  0.1% 0.001:1 PMMA Acetonitrile 20% 5:1 0.4 340 No light  4 830 0.1% 0.001:1 PVB MeOH 20% 5:1 0.4 54 FLE n/a n/a 0.4 340 1.32 0.3790.367 2 340 3.41 0.359 0.313 5 340 4.68 0.329 0.283 10 340 6.95 0.310.262 15 340 7.29 0.299 0.246 20 340 7.38 0.285 0.236  5 830  0.1%0.001:1 PVDF Terp- 25% 4:1 0.4 31 FLE EDGA 0.4 340 11.8 0.376 0.377 2340 34.1 0.345 0.333 5 340 50.2 0.319 0.303 10 340 76.4 0.299 0.280 15340 88.1 0.281 0.260 20 340 95.6 0.270 0.255  6 830  0.1% 0.001:1 PVBMeOH 20% 5:1 0.4 27.6 FLE 0.4 340 5.77 0.372 0.366 2 340 15.3 0.3390.317 5 340 21.7 0.308 0.283 10 340 31.4 0.287 0.258 15 340 34.3 0.2720.241 20 340 35.9 0.263 0.231  7 830  0.5% 0.005:1 PMMA Acetonitrile 20%5:1 0.4 50 FLE 0.4 340 2.82 0.411 0.367 2 340 8.33 0.379 0.324 5 34012.4 0.346 0.294 10 340 17 0.320 0.268 15 340 20.1 0.305 0.265 20 34020.1 0.297 0.270  8 830  0.5% 0.005:1 PVDF Terp- 25% 4:1 0.4 46 FLE EDGA0.4 340 9.6 0.415 0.378 2 340 27.7 0.390 0.34 5 340 39.9 0.361 0.312 10340 50.6 0.337 0.289 15 340 52 0.327 0.278 20 340 51.2 0.309 0.27  9 830 0.1% 0.001:1 PVDF Terp- 25% 4:1 0.4 30 FLE EDGA 0.4 340 12.3 0.3610.377 2 340 35.6 0.33 0.327 5 340 53.3 0.3 0.293 10 340 84.7 0.278 0.26915 340 96.4 0.262 0.255 20 340 104 0.251 0.246 10 TNE  0.5% 0.005:1 PMMAAdetonitrile 20% 5:1 0.4 110 FLE 0.4 340 0.11 0.531 0.468 2 340 0.150.457 0.467 5 340 0.18 0.466 0.468 10 340 0.23 0.408 0.447 15 340 0.210.39 0.453 20 340 0.21 0.437 0.457 11A TNE  0.5% 0.005:1 PVDF Terp- 25%4:1 0.4 29.4 FLE EDGA 0.4 340 10.1 n/a n/a 2 340 31.2 0.302 0.279 5 34047.3 0.271 0.239 10 340 68.7 0.252 0.213 15 340 76.6 0.241 0.2 20 34089.6 0.235 0.195 11B TNE   1% 0.01:1 PVDF Terp- 25% 4:1 0.4 35.2 FLEEDGA 0.4 340 7.01 n/a n/a 2 340 21.1 0.317 0.293 5 340 33.8 0.289 0.25610 340 43.5 0.266 0.226 15 340 49.4 0.254 0.212 20 340 54.9 0.246 0.20412 TNE  0.1% 0.001:1 PMMA Acetonitrile 20% 5:1 0.4 38 FLE 0.4 340 8.350.353 0.364 2 340 23.2 0.327 0.31 5 340 33.5 0.299 0.273 10 340 45.70.278 0.243 15 340 46.3 0.266 0.23 20 340 42.8 0.259 0.222 13 TNE  0.1%0.001:1 PVB MeOH 20% 5:1 0.4 45.2 FLE 0.4 340 2.77 0.328 0.34 2 340 7.50.3 0.277 5 340 10.4 0.273 0.24 10 340 13.7 0.253 0.215 15 340 14.20.248 0.211 14 TNE  0.5% 0.005:1 PS Xylene 10% 10:1 0.4 47.6 FLE 0.4 3401.61 n/a n/a 2 340 4.65 n/a n/a 5 340 7.38 n/a n/a 10 340 8.51 0.3180.249 15 340 9.8 0.305 0.235 20 340 11 0.297 0.226 15 TNE  0.1% 0.001:1PVB MeOH 20% 5:1 0.4 46 FLE 0.4 340 3.78 0.321 0.336 2 340 10.8 0.2920.275 5 340 17 0.266 0.237 10 340 18.3 0.246 0.208 15 340 19.8 0.2360.20 16A TNE  0.1% 0.001:1 PVDF Terp- 25% 4:1 0.4 43 FLE EDGA 0.4 34016.2 0.318 0.33 2 340 47.9 0.289 0.273 5 340 75 0.263 0.236 10 340 87.50.243 0.209 15 340 97.9 0.234 0.201 20 340 104 0.236 0.212 16B TNE   1%0.01:1 PMMA DCE 10% 10:1 0.4 84.8 FLE 0.4 340 0.06 n/a n/a 2 340 0.18n/a n/a 5 340 0.26 n/a n/a 10 340 0.24 n/a n/a 15 340 0.2 n/a n/a 20 3400.15 n/a n/a 17A TNE  0.1% 0001.1 PMMA Acetonitrile 20% 5:1 0.4 136 FLE0.4 340 0.15 0.414 0.505 2 340 0.29 0.369 0.443 5 340 0.44 0.325 0.41610 340 0.65 0.307 0.368 15 340 0.72 0.304 0.334 20 340 0.75 0.287 0.3417B TNE  0.5% 0.005:1 PMMA Acetonitrile 20% 5:1 0.4 40 FLE 0.4 340 2.230.406 0.385 2 340 6.41 0.375 0.33 5 340 9.16 0.347 0.294 10 340 13.40.325 0.267 15 340 14.2 0.312 0.252 20 340 14.5 0.302 0.24 18 TNE  0.1%0.001:1 PVDF Terp- 25% 4:1 0.4 40 FLE EDGA 0.4 340 18.5 0.325 0.314 2340 55.3 0.297 0.283 5 340 82.6 0.27 0.246 10 340 101 0.253 0.228 15 340102 0.249 0.227 20 340 95.6 0.25 0.236 19 GGS   0% 0 PVDF Terp- 25% 4:10.4 39.2 FLE EDGA 0.4 340 15.4 0.294 0.335 2 340 44.9 0.263 0.26 5 34070.3 0.241 0.222 10 340 83.4 0.226 0.197 15 340 97.2 0.219 0.189 20 340101 0.216 0.188 20 GGS   0% 0 PVDF Terp- 25% 4:1 0.4 34.8 FLE EDGA 0.4340 13.1 0.295 0.336 2 340 40.2 0.263 0.262 5 340 67.5 0.241 0.223 10340 92 0.225 0.198 15 340 110 0.217 0.187 20 340 125 0.213 0.182 21 TNE  0% 0 PVDF Terp- 25% 4:1 0.4 31.8 FLE EDGA 0.4 340 21.3 0.270 0.31 2340 62.3 0.247 0.249 5 340 100 0.226 0.213 10 340 116 0.212 0.188 15 340127 0.204 0.177 20 340 138 0.201 0.176 22 TNE   0% 0 PVDF Terp- 25% 4:10.4 69.4 FLE EDGA 0.4 340 20.7 0.275 0.328 2 340 61.2 0.250 0.262 5 340102 0.228 0.222 10 340 129 0.211 0.194 15 340 160 0.203 0.182 20 340 1780.198 0.176 23 TNE 0.05% 0.0005:1 PVDF Terp- 25% 4:1 0.4 35.6 FLE EDGA0.4 340 17.2 0.328 0.338 2 340 49 0.301 0.281 5 340 75.9 0.274 0.245 10340 83.4 0.254 0.219 15 340 90.8 0.246 0.212 20 340 85.5 0.243 0.213 24TNE 0.05% 0.0005:1 PMMA THF 20% 5:1 0.4 61.4 FLE 0.4 340 1.6 n/a n/a 2340 4.39 n/a n/a 5 340 6.33 n/a n/a 10 340 6.56 0.263 0.224 15 340 6.640.255 0.214 20 340 6.44 0.251 0.214 25 TNE 0.05% 0.0005:1 PS Xylene 20%5:1 0.4 42.5 FLE 0.4 340 6.42 n/a n/a 2 340 19.1 0.310 0.289 5 340 30.60.284 0.256 10 340 35.3 0.264 0.226 15 340 36.7 0.253 0.213 20 340 38.20.247 0.208 26 TNE  0.5% 0.005:1 PVB MeOH 20% 5:1 0.4 39 FLE 0.4 3404.32 0.359 0.344 2 340 12.5 0.326 0.286 5 340 18.2 0.296 0.249 10 34026.4 0.275 0.221 15 340 28.3 0.262 0.207 20 340 28.9 0.255 0.200 27 TNE 0.5% 0.005:1 PVB MeOH 20% 5:1 0.4 102 FLE 0.4 340 5.11 0.345 0.361 2340 14.4 0.311 0.297 5 340 21.8 0.280 0.254 10 340 32.2 0.259 0.223 15340 35.6 0.245 0.206 20 340 37.6 0.237 0.195 28 830   0% 0 PVDF Terp-25% 4:1 0.4 31 FLE EDGA 0.4 340 20.6 0.294 0.343 2 340 58.3 0.271 0.2895 340 86.6 0.249 0.256 10 340 122 0.232 0.23 15 340 131 0.223 0.218 20340 130 0.217 0.215 29 830   0% 0 PMMA Acetonitrile 20% 5:1 0.4 35 FLE0.4 340 8.99 0.295 0.342 2 340 25.8 0.272 0.287 5 340 38 0.251 0.253 10340 52.1 0.234 0.229 15 340 56.4 0.224 0.22 20 340 54.5 0.22 0.217 30830   0% 0 PVB MeOH 20% 5:1 0.4 32 FLE 0.4 340 8.99 0.291 0.34 2 34027.2 0.271 0.289 5 340 40.7 0.25 0.253 10 340 57.1 0.233 0.228 15 34061.9 0.224 0.220 20 340 58.5 0.219 0.214 Notes: ^(a)Phosphors areparticulate; “830”, “TNE”, and “GGS” (“white”) phosphors from SylvaniaCorporation; ^(b)The light-emitting material in each case waspoly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], (MEHPPV).^(c)Dichloroethane (DCE) was used as the solvent for MEHPPV in thosedevices that included MEHPPV. ^(d)Binders used includedpolymethylmethacrylate (PMMA), polystyrene (PS),poly(vinylidenedifluoride) (PVDF), and polyvinylbutyral (PVB).^(e)Binder solvents that were used included tetrahydrofuran (THF),xylene, methanol (MeOH), acetonitrile, dichloroethane (DCE), andterpinol mixed isomers blended with ethyldiglycol acetate (Terp-EDGA).^(f)Illumination intensity and color measurements were taken in a lightcontrolled room where all the extraneous light is eliminated and onlythe light radiating from the device under test is sensed and measured.The measurements were taken with a Minolta brand Chroma Meter, ModelCS-100A. This meter measures both Luminance and Chromaticity values, andreads out in Y,x, y. The luminance (Y) is measured in candellas persquare meter, and is currently referred to as NITS. The chromaticity orcolor is measured in what is known as the “1931 CIE Color System” usingthe units x, y. The x, y values are coordinates representing the colorin two dimensional space, independent of intensity, on a graph known asthe “1931 x, y chromaticity diagram”. The term “n/a” means that the datawas not available. ^(g)The voltage at which light emission was firstdetected at a frequency of 400 Hz was recorded as First Emitted Light(FLE).

EXAMPLE 3

This illustrates the construction of an electroluminescent device.

With reference to FIG. 8, a first electrode 201 is printed onto asuitable substrate (501) in a desired pattern or patterns. Next, alight-emitting layer (105), comprising light-emitting particles (103) ina dielectric binder material (601), is printed onto the first electrodepatterns. Then, a transparent second electrode (202)is printed onto thelight-emitting layer (105).

After curing the light-emitting layer (105), a front outlining electrodelead (FOEL) (903) is printed onto the second electrode (202).Appropriate connection leads (Ag or C) to the first electrode (901) andto the FOEL (902) are then printed.

The first electrode and the second electrode may be fabricated usingconductive polymers to provide a totally polymeric system without metalsor metallic compounds.

FIG. 9 is a schematic illustration of an alternative embodiment of anelectroluminescent (EL) multi-segment display device comprising asubstrate (501), a first electrode layer (201), a dielectric layer (701,a light-emitting layer (105), an electrically conductive layer, orsecond electrode (202), and a front outlining electrode lead (903). Thesubstrate (501) may comprise either metal or an electricallynon-conducting material. If, for example, an aluminum substrate is used,then it is first coated with an insulative material.

The first electrode (201) is formed of an electrically conductivematerial, for example, silver or carbon particles. Dielectric layer(701) is formed of high dielectric constant material, such as bariumtitanate. The illumination layer (105) is formed of light-emittingparticles (103) mixed with a dielectric binder (601), as describedabove. The second electrode (202) may be formed of indium tin oxide(ITO), silver particles, or other electrically conductive material.

The present device can be fabricated by first printing the firstelectrode (201) onto the substrate (501). If the substrate is a metal orother conductor, such as aluminum, then an insulative coating is firstapplied over the substrate using a compound such as Nazdar's PlasticPlus (Nazdar Mid-America, St. Louis, Mo.). If the substrate is formedfrom a non-conductor, such as a polyester film, polycarbonate, or otherplastic material, no coating is required.

The first electrode (201) is applied over a front surface of thesubstrate (501). In an exemplary embodiment, the first electrode (201)is formed of conductive particles, for example, silver or carbon,dispersed in a polymeric or other binder to form a screen printable ink.In one embodiment, the first electrode may comprise a silver particleink such as DuPont 7145. Alternatively, the first electrode may comprisea conductive polymer such as polyaniline, polypyrrole, andpoly(3,4-ethylenedioxythiophene). In an exemplary embodiment, a carbonfirst electrode may have a thickness of between approximately 0.2millimeters and 0.6 millimeters. However, any suitable electrodethickness may be employed. It is to be noted that the first electrodelayer (201), as well as each of the layers that are successively appliedin fabricating the device (101), may be applied by any appropriatemethod, including an ink jet process, a stencil, flat coating, brushing,rolling, spraying, etc.

The first electrode layer (201) may cover the entire substrate (501),but this layer typically covers only the illumination area (the areacovered by the light-emitting layer (105), described below).

After the first electrode layer is cured, an optional dielectric layer(701) can be applied over the first electrode layer (201). In anexemplary embodiment, a dielectric layer comprises a high dielectricconstant material, such as barium titanate dispersed in a polymericbinder to form a screen printable ink. In one embodiment, the dielectricmay be an ink, such as DuPont 7153. The dielectric layer (701) may coverthe substrate either entirely, or may alternatively cover only theillumination area. Alternatively, the dielectric layer (701) may includea high dielectric constant material such as alumina oxide dispersed in apolymeric binder. The alumina oxide layer can be applied over the firstelectrode and cured by exposure to UV light. In an exemplary embodiment,the dielectric layer (701) may have a thickness of between approximately20 microns and 31 microns.

In one embodiment, the dielectric layer has substantially the same shapeas the illumination area, but extends approximately 1/16″ to ⅛″ beyondthe illumination area. Alternatively, the dielectric layer may coversubstantially all of the substrate (501).

Upon curing the dielectric layer (701), the illumination layer (105) isapplied over the dielectric layer. The illumination layer (105) isformulated in accordance with the process described above. The size ofthe illumination area covered by the illumination layer (105) may rangefrom approximately 1 sq. mm to 1000 sq. cm., or more. In an exemplaryembodiment of the present system, the illumination layer compriseslight-emitting material-coated phosphor particles (103), and has athickness of between approximately 20 microns and 31 microns.

Next, the second electrode (202) is printed over the light-emittinglayer (105), extending about 1/16″ to ⅛″ beyond the area covered by thelight-emitting layer (105). The distance beyond the illumination layerto which the second electrode (202) extends is a function of the size ofthe device. Accordingly, the extension of the second electrode (202)beyond the illumination area may advantageously be between approximately2 percent and 10 percent of the width of the illumination layer. In anexemplary embodiment, the second electrode (202) comprises indium tinoxide (ITO) particles in the form of a screen printable ink such asDuPont 7160. In an alternative embodiment, the second electrode isnon-metallic and is translucent or transparent, and comprises aconductive polymer, such as polyaniline, polypyrrole, orpoly(3,4-ethylenedioxythiophene). In an exemplary embodiment, an ITOconductive layer (202) may have a thickness of between approximately 5microns and 13 microns.

Next, a front outlining electrode layer 903, comprising a conductivematerial such as silver or carbon, is applied onto the outer perimeterof the second electrode (202) to transport electrical current thereto.The front electrode lead (903) is typically a 1/16″ to ⅛″ wide strip,approximately 2 percent to 20 percent of the width of the secondelectrode (202) depending on the current drawn by device 101 and thelength of the device from the controller or power source. For example,the front electrode lead (903) may be approximately ⅛″ wide for a 50″wire run from the controller.

The front outlining electrode leads (903) may be screen printed onto thesecond electrode (202), or may be fabricated as interconnect tabsextending beyond the substrate to facilitate connection to a powersource or controller. In one embodiment, the front outlining electrodelayer contacts substantially the entire outer perimeter of the secondelectrode layer (202) and does not overlap the first electrode (201). Inan alternative embodiment, the front electrode lead (903) contacts onlyabout 25% of outer perimeter of the second electrode (202). The frontelectrode lead (903) may be fabricated to contact any amount of theouter perimeter of the second electrode (202), from about 25% to about100%. The front outlining electrode lead (903) may, for example,comprise silver particles that form a screen-printable ink, such asDuPont 7145. In an alternative embodiment, front outlining electrodelead (903) is non-metallic and is translucent or transparent, andcomprises a conductive polymer, such as polyaniline, polypyrrole, orpoly(3,4-ethylenedioxythiophene). Fabricating the first and the secondelectrodes and the front outlining electrode lead with polymers such asthe aforementioned compounds would make device 101 more flexible, aswell as more durable and corrosion resistant. In an exemplaryembodiment, a silver front outlining electrode layer (903) may have athickness of between approximately 20 microns and 28 microns.

The electroluminescent device (101) that is fabricated by this methodcan be connected to a source of alternating current as shown in FIG. 10,for example, in order to provide an operating electroluminescent system.If desired, a battery can be used to supply the current in conjunctionwith suitable phase inverting devices. Any number and type of otherelectrical plugs, timers, connectors, switches, and the like can also beadded to the circuit in which the electroluminescent device is placed.

All references cited in this specification, including without limitationall papers, publications, patents, patent applications, presentations,texts, reports, manuscripts, brochures, books, internet postings,journal articles, periodicals, and the like, are hereby incorporated byreference into this specification in their entireties. The discussion ofthe references herein is intended merely to summarize the assertionsmade by their authors and no admission is made that any referenceconstitutes prior art. Applicants reserve the right to challenge theaccuracy and pertinency of the cited references.

In view of the above, it will be seen that the several advantages of theinvention are achieved and other advantageous results obtained.

As various changes could be made in the above methods and compositionswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

1. A luminescent device comprising an electroluminescent phosphor in operative contact with a light-emitting material, both of which are located between a first electrode and a second electrode, wherein the first electrode and the second electrode are free of metals and metal oxides and wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material.
 2. The device according to claim 1, wherein the electroluminescent phosphor is present in an insulating layer which is located between the first electrode and the second electrode.
 3. The device according to claim 1, wherein the first electrode and the second electrode comprise an intrinsically conductive polymer.
 4. The device according to claim 3, wherein the first electrode and the second electrode comprise a substituted or unsubstituted intrinsically conductive polymer that is selected from the group consisting of polyaniline, polyacetylene, poly-p-phenylene, poly-m-phenylene, polyphenylene sulfide, polypyrrole, polythiophene, and polycarbazole.
 5. The device according to claim 4, wherein the first electrode and the second electrode comprise poly(3,4-ethylenedioxythiophene).
 6. The device according to claim 2, wherein the light-emitting material is located in the insulating layer.
 7. The device according to claim 2, wherein the electroluminescent phosphor can be excited by an alternating current electric field and can emit light at a first wavelength.
 8. The device according to claim 1, wherein the electroluminescent phosphor is selected from the group consisting of: CdSe; InAs; LaPO₄, undoped or doped with one or more of Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; ZnS, undoped, or doped with Ag, Cu, Mn, Tb, TbF, or TbF₃; ZnSe; undoped or doped with Mn, or Cu; ZnCdS; M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba, and M^(III)=Al, Ga, In, Y, or is optionally absent, where the compound is undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures thereof.
 9. The device according to claim 1, wherein the electroluminescent phosphor is in the form of particles.
 10. The device according to claim 1, wherein the electroluminescent phosphor is an organic material.
 11. The device according to claim 1, wherein the light-emitting material is a material which is excited when in operative contact with the excited electroluminescent phosphor and which is capable of emitting light of a wavelength that is different than the light emitted by the electroluminescent phosphor.
 12. The device according to claim 11, wherein the light-emitting material is an inorganic solid that is selected from the group consisting of LaPO₄, undoped or doped with one or more of Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba, and M^(III)=Al, Ga, In, Y, or is optionally absent, and where the compound is undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures thereof.
 13. The device according to claim 11, wherein the light-emitting material is an organic material.
 14. The device according to claim 13, wherein the light-emitting material is selected from the group consisting of: anthracene, undoped or doped with tetracene, aluminum tris(8-hydroxyquinolinate), poly-(p-phenylenevinylene) (PPV), poly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene] (MEH-BP-PPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene (MEH-CN-PPV), poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-1,2-ethylene-1,4-phenylene] (DiSiPV), Tb tris(acetylacetonate), Eu(1,10-phenanthroline)-tris(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate, Eu tris(dibenzoylmethanato)phenanthroline, Tb tris(acetylacetonate)phenanthroline, Eu(4,7-diphenyl phenanthroline)-tris(4,4,4-trifluoro)-1-(2-thienyl)-butane-1,3-dionate, Nd(4,7-diphenylphenanthroline)(dibenzoylmethanato)₃, Eu(dibenzolmethanato)₃-2-(2-pyridyl)benzimidazole, Eu(dibenzolmethanato)₂-1-ethyl-2-(2-pyridyl)benzimidazole, Tb-[3-(5-phenyl-1,3,4-oxadiazol-2-yl)-2,4-pentanedionate]₃, lanthanide-tris(4-methylbenzoate), lanthanide-tris(4-methoxybenzoate), Tb tris(4-methylbenzoate), Tb tris(4-methoxybenzoylbenzoate), Eu tris(4-methoxybenzoylbenzoate), Tb-tris(tetradecylphethalate)phenanthroline, Tb-imidodiphosphinate, Tb 1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one, polypyridine; poly(p-phenylenevinylene), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene)-alt-co-(4,4′-biphenylenevinylene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(4,4′-biphenylene)], poly[{9,9-dioctyl-2,7-divinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene}], poly[{9,9-dioctyl-2,7-bis(2-cyanovinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylenephenylene)], poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene}-alt-co-{2,5-bis(N,N′-diphenylamino)-1,4-phenylene}], poly[{9-ethyl-3,6-bis(2-cyanovinylene)carbazolylene)}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[(9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di-(p-butylphenyl)-1,4-diaminobenzene], poly[2-(6-cyano-6-methylheptyloxy)-1,4-phenylene), poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-ethylenylbenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], poly[(9,9-dihexylfluorenyl-2,7-divinylenefluorenylene)], poly[(9,9-dihexyl-2,7-(2-cyanodivinylene)-fluorenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly(9,9-dioctylfluorenyl-2,7-diyl, poly(9,9-dihexylfluorenyl-2,7-diyl), poly[9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di(p-butyloxyphenyl)-1,4-diaminobenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-diphenyl)-N,N′-di(p-butyloxy-phenyl)-1,4-diaminobenzene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,10-anthracene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-bis{4-butylphenyl}-benzidine-N,N′-{1,4-diphenylene})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(2-methoxy-5-{2-ethylhexyloxy}-1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9′-spirobifluorene-2,7-diyl], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(2,5-p-xylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(3,5-pyridine)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9-di-{5-pentanyl}-fluorenyl-2′,7′-diyl; poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′{2,2′-bipyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′-{2,2′:6′,2″-terpyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N′bis{p-butylphenyl}-1,4-diaminophenylene)], 8-hydroxyquinoline, fluorescein, rhodamine, xanthene (substituted or unsubstituted), substituted coumarin, substituted hydroxycoumarin, substituted or unsubstituted tetra-cyanoquinolines, ethidium bromide, propidium iodide, benzoxanthene yellow, bixbenzimide ((2′-[4-hydroxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol), (2′-[4-ethoxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol)), 4,6-diamidino-2-phenylindole (DAPI), lithium tetra(2-methyl-8-hydroxyquinolinato)boron, bis(8-hydroxyquinolinato)zinc, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(2-phenylpyridine)iridium(III); and tris(8-hydroxyquinolinato)gallium(III), tris(8-hydroxyquinolato)aluminum, tetra(2-methyl-8-hydroxyquinolato)boron, lithium salt, 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, 9,10-di[(9-ethyl-3-carbazoyl)-vinylenyl)]-anthracene, 4,4′-bis(diphenylvinylenyl)-biphenyl, 1,4-bis(9-ethyl-3-carbazovinylene)-2-methoxy-5-(2-ethylhexyloxy)benzene, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(5-aminophenanthroline)europium(III), tris(dinapthoylmethane)mono(phenanthroline)europium(III), tris(biphenoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-diphenylphenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dimethyl-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxy-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxyloxy-phenanthroline)europium(III), lithium tetra(8-hydroxyquinolinato)boron; 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, bis(8-hydroxyquinolinato)zinc, bis(2-methyl-8-hydroxyquinolinato)zinc, iridium(III) tris(2-phenylpyridine), tris(8-hydroxyquinoline)aluminum, tris[1-phenyl-3-methyl-4-(2,2-dimethylpropan-1-oyl)-pyrazolin-5-one]-terbium, and mixtures of two or more of any of these.
 15. The device according to claim 11, wherein the light-emitting material is one that is not excited by an alternating current electrical field.
 16. The device according to claim 6, wherein the electroluminescent phosphor is in the form of particles which are in direct contact with the light-emitting material.
 17. The device according to claim 16, wherein the electroluminescent phosphor particles are coated with the light-emitting material.
 18. The device according to claim 17, wherein the electroluminescent phosphor particles comprise ZnS:Cu which are coated with poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene].
 19. The device according to claim 11, wherein the wavelength of light emitted by the light-emitting material is in the range of infrared, visible, or ultraviolet.
 20. The device according to claim 6, wherein one or more dielectric layers that are separate from the insulating layer are present between the first electrode and the second electrode.
 21. The device according to claim 6, wherein the first electrode or the second electrode is located adjacent a substrate that is plastic film or fabric.
 22. The device according to claim 1, wherein at least two separate light-emitting materials are present, at least one of which is excited by excitation of the electroluminescent phosphor and at least one other of which emits light upon being excited by the excitation of a light-emitting material.
 23. A method of making an electroluminescent device comprising the steps: placing a phosphor and an insulating layer between a first electrode and a second electrode; and placing a light-emitting material in operative contact with the phosphor, wherein the light-emitting material is placed between the first electrode and the second electrode and the first electrode and the second electrode are free of metals and metal oxides and wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material.
 24. The method according to claim 23, wherein the phosphor is in direct contact with the light-emitting material.
 25. The method according to claim 24, wherein the phosphor is in particulate form and is coated with the light-emitting material to form light-emitting particles.
 26. The method according to claim 25, wherein the light-emitting particles are mixed with a dielectric material to form a light-emitting layer.
 27. The method according to claim 26, wherein the first electrode is located adjacent a substrate.
 28. The method according to claim 27, wherein a dielectric layer is placed between the first electrode and the light-emitting layer.
 29. The method according to claim 23, wherein the first electrode and the second electrode comprise an intrinsically conductive polymer.
 30. The method according to claim 29, wherein the phosphor comprises a material that is selected from the group consisting of LaPO₄, undoped or doped with one or more of Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba and M^(III)=Al, Ga, In, or Y, undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures thereof.
 31. The method according to claim 23, wherein the light-emitting material is an organic material.
 32. The method according to claim 31, wherein the light-emitting material is selected from the group consisting of: anthracene, undoped or doped with tetracene, aluminum tris(8-hydroxyquinolinate), poly-(p-phenylenevinylene) (PPV), poly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene] (MEH-BP-PPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene (MEH-CN-PPV), poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-1,2-ethylene-1,4-phenylene] (DiSiPV), Tb tris(acetylacetonate), Eu(1,10-phenanthroline)-tris(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate, Eu tris(dibenzoylmethanato)phenanthroline, Tb tris(acetylacetonate)phenanthroline, Eu(4,7-diphenylphenanthroline)-tris(4,4,4-trifluoro)-1-(2-thienyl)-butane-1,3-dionate, Nd(4,7-diphenylphenanthroline)(dibenzoylmethanato)₃, Eu(dibenzolmethanato)₃-2-(2-pyridyl)benzimidazole, Eu(dibenzolmethanato)₂-1-ethyl-2-(2-pyridyl)benzimidazole, Tb-[3-(5-phenyl-1,3,4-oxadiazol-2-yl)-2,4-pentanedionate]₃, lanthanide-tris(4-methylbenzoate), lanthanide-tris(4-methoxybenzoate), Tb tris(4-methylbenzoate), Tb tris(4-methoxybenzoylbenzoate), Eu tris(4-methoxybenzoylbenzoate), Tb-tris(tetradecylphethalate)phenanthroline, Tb-imidodiphosphinate, Tb 1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one, polypyridine; poly(p-phenylenevinylene), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene)-alt-co-(4,4′-biphenylenevinylene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(4,4′-biphenylene)], poly[{9,9-dioctyl-2,7-divinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene}], poly[{9,9-dioctyl-2,7-bis(2-cyanovinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylenephenylene)], poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene}-alt-co-{2,5-bis(N,N′-diphenylamino)-1,4-phenylene}], poly[{9-ethyl-3,6-bis(2-cyanovinylene)carbazolylene)}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[(9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di-(p-butylphenyl)-1,4-diaminobenzene], poly[2-(6-cyano-6-methylheptyloxy)-1,4-phenylene), poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-ethylenylbenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], poly[(9,9-dihexylfluorenyl-2,7-divinylenefluorenylene)], poly[(9,9-dihexyl-2,7-(2-cyanodivinylene)-fluorenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly(9,9-dioctylfluorenyl-2,7-diyl, poly(9,9-dihexylfluorenyl-2,7-diyl), poly[9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di(p-butyloxyphenyl)-1,4-diaminobenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-diphenyl)-N,N′-di(p-butyloxy-phenyl)-1,4-diaminobenzene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,10-anthracene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-bis{4-butylphenyl}-benzidine-N,N′-{1,4-diphenylene})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(2-methoxy-5-{2-ethylhexyloxy}-1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9′-spirobifluorene-2,7-diyl], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(2,5-p-xylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(3,5-pyridine)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9-di-{5-pentanyl}-fluorenyl-2′,7′-diyl; poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′{2,2′-bipyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′-{2,2′:6′,2″-terpyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N′bis{p-butylphenyl}-1,4-diaminophenylene)], 8-hydroxyquinoline, fluorescein, rhodamine, xanthene (substituted or unsubstituted), substituted coumarin, substituted hydroxycoumarin, substituted or unsubstituted tetra-cyanoquinolines, ethidium bromide, propidium iodide, benzoxanthene yellow, bixbenzimide ((2′-[4-hydroxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol), (2′-[4-ethoxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol)), 4,6-diamidino-2-phenylindole (DAPI), lithium tetra(2-methyl-8-hydroxyquinolinato)boron, bis(8-hydroxyquinolinato)zinc, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(2-phenylpyridine)iridium(III); and tris(8-hydroxyquinolinato)gallium(III), tris(8-hydroxyquinolato)aluminum, tetra(2-methyl-8-hydroxyquinolato)boron, lithium salt, 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, 9,10-di[(9-ethyl-3-carbazoyl)-vinylenyl)]-anthracene, 4,4′-bis(diphenylvinylenyl)-biphenyl, 1,4-bis(9-ethyl-3-carbazovinylene)-2-methoxy-5-(2-ethylhexyloxy)benzene, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(5-aminophenanthroline)europium(III), tris(dinapthoylmethane)mono(phenanthroline)europium(III), tris(biphenoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-diphenylphenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dimethyl-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxy-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxyloxy-phenanthroline)europium(III), lithium tetra(8-hydroxyquinolinato)boron; 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, bis(8-hydroxyquinolinato)zinc, bis(2-methyl-8-hydroxyquinolinato)zinc, iridium(III) tris(2-phenylpyridine), tris(8-hydroxyquinoline)aluminum, tris[1-phenyl-3-methyl-4-(2,2-dimethylpropan-1-oyl)-pyrazolin-5-one]-terbium, and mixtures of two or more of any of these.
 33. The method according to claim 23, wherein all steps are carried out under ambient conditions of temperature and atmosphere.
 34. An electroluminescent display comprising an electroluminescent phosphor in operative contact with a light-emitting material wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material; and a first electrode and a second electrode, between which is located the electroluminescent phosphor and an insulating layer.
 35. A method of providing light comprising applying an AC electrical field to a luminescent device comprising an electroluminescent phosphor which is in operative contact with a light-emitting material, wherein both the electroluminescent phosphor and the light-emitting material are located between a first electrode and a second electrode, wherein the first electrode and the second electrode are free of metal or metal oxides, and wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material.
 36. The method according to claim 35, wherein the electroluminescent phosphor is present in an insulating layer which is located between a first electrode and a second electrode.
 37. The method according to claim 36, wherein the first electrode and the second electrode are free of metals and metal oxides.
 38. The method according to claim 35, wherein the electroluminescent phosphor is in the form of particles which are in direct contact with the light-emitting material.
 39. The method according to claim 35, wherein the electroluminescent phosphor particles are coated with the light-emitting material.
 40. The method according to claim 35, wherein the electroluminescent phosphor particles comprise ZnS:Cu which are coated with poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene].
 41. The method according to claim 35, wherein the wavelength of light emitted by the light-emitting material is in the range of infrared, visible, or ultraviolet.
 42. The method according to claim 35, wherein the wavelength of light emitted by the light-emitting material comprises infrared light.
 43. The method according to claim 36, wherein at least one of the first electrode or the second electrode comprises an intrinsically conductive polymer.
 44. The method according to claim 36, wherein the first electrode and the second electrode comprise a substituted or unsubstituted intrinsically conductive polymer that is selected from the group consisting of polyaniline, polyacetylene, poly-p-phenylene, poly-m-phenylene, polyphenylene sulfide, polypyrrole, polythiophene, and polycarbazole.
 45. The method according to claim 36, wherein the first electrode and the second electrode comprise poly(3,4-ethylenedioxythiophene).
 46. The method according to claim 36, wherein the light-emitting material is located in the insulating layer.
 47. The method according to claim 35, wherein the electroluminescent phosphor is selected from the group consisting of: CdSe; InAs; LaPO₄, undoped or doped with one or more of Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; ZnS, undoped, or doped with Ag, Cu, Mn, Tb, TbF, or TbF₃; ZnSe; undoped or doped with Mn, or Cu; ZnCdS; M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba, and M^(III)=Al, Ga, In, Y, or is optionally absent, where the compound is undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures thereof.
 48. The method according to claim 35, wherein the light-emitting material is a material which is excited when in operative contact with the excited electroluminescent phosphor and which is capable of emitting light of a wavelength that is different than the light emitted by the electroluminescent phosphor.
 49. The method according to claim 35, wherein the light-emitting material is an organic material.
 50. The method according to claim 35, wherein the light-emitting material is selected from the group consisting of: anthracene, undoped or doped with tetracene, aluminum tris(8-hydroxyquinolinate), poly-(p-phenylenevinylene) (PPV), poly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene] (MEH-BP-PPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene (MEH-CN-PPV), poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-1,2-ethylene-1,4-phenylene] (DiSiPV), Tb tris(acetylacetonate), Eu(1,10-phenanthroline)-tris(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate, Eu tris(dibenzoylmethanato)phenanthroline, Tb tris(acetylacetonate)phenanthroline, Eu(4,7-diphenylphenanthroline)-tris(4,4,4-trifluoro)-1-(2-thienyl)-butane-1,3-dionate, Nd(4,7-diphenylphenanthroline)(dibenzoylmethanato)₃, Eu(dibenzolmethanato)₃-2-(2-pyridyl)benzimidazole, Eu(dibenzolmethanato)₂-1-ethyl-2-(2-pyridyl)benzimidazole, Tb-[3-(5-phenyl-1,3,4-oxadiazol-2-yl)-2,4-pentanedionate]₃, lanthanide-tris(4-methylbenzoate), lanthanide-tris(4-methoxybenzoate), Tb tris(4-methylbenzoate), Tb tris(4-methoxybenzoylbenzoate), Eu tris(4-methoxybenzoylbenzoate), Tb-tris(tetradecylphethalate)phenanthroline, Tb-imidodiphosphinate, Tb 1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one, polypyridine; poly(p-phenylenevinylene), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene)-alt-co-(4,4′-biphenylenevinylene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(4,4′-biphenylene)], poly[{9,9-dioctyl-2,7-divinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene}], poly[{9,9-dioctyl-2,7-bis(2-cyanovinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylenephenylene)], poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene}-alt-co-{2,5-bis(N,N′-diphenylamino)-1,4-phenylene}], poly[{9-ethyl-3,6-bis(2-cyanovinylene)carbazolylene)}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[(9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di-(p-butylphenyl)-1,4-diaminobenzene], poly[2-(6-cyano-6-methylheptyloxy)-1,4-phenylene], poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-ethylenylbenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], poly[(9,9-dihexylfluorenyl-2,7-divinylenefluorenylene)], poly[(9,9-dihexyl-2,7-(2-cyanodivinylene)-fluorenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly(9,9-dioctylfluorenyl-2,7-diyl, poly(9,9-dihexylfluorenyl-2,7-diyl), poly[9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di(p-butyloxyphenyl)-1,4-diaminobenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-diphenyl)-N,N′-di(p-butyloxy-phenyl)-1,4-diaminobenzene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,10-anthracene)], poly[(9,9-dioctylfluoren-2,7-diyl)-alt-co-(N,N′-bis{4-butylphenyl}-benzidine-N,N′-{1,4-diphenylene})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9′-spirobifluorene-2,7-diyl], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(2,5-p-xylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(3,5-pyridine)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9-di-{5-pentanyl}-fluorenyl-2′,7′-diyl; poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′{2,2′-bipyridine})], poly[(9,9-dihexylfluorenyl-2.7-diyl)-co-(6,6′-{2,2′:6′,2″-terpyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N′bis(p-butylphenyl)-1,4-diaminophenylene)], 8-hydroxyquinoline, fluorescein, rhodamine, xanthene (substituted or unsubstituted), substituted coumarin, substituted hydroxycoumarin, substituted or unsubstituted tetra-cyanoquinolines, ethidium bromide, propidium iodide, benzoxanthene yellow, bixbenzimide ((2′-[4-hydroxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol), (2′-[4-ethoxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol)), 4,6-diamidino-2-phenylindole (DAPI), lithium tetra(2-methyl-8-hydroxyquinolinato)boron, bis(8-hydroxyquinolinato)zinc, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(2-phenylpyridine)iridium(III); and tris(8-hydroxyquinolinato)gallium(III), tris(8-hydroxyquinolato)aluminum, tetra(2-methyl-8-hydroxyquinolato)boron, lithium salt, 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, 9,10-di[(9-ethyl-3-carbazoyl)-vinylenyl)]-anthracene, 4,4′-bis(diphenylvinylenyl)-biphenyl, 1,4-bis(9-ethyl-3-carbazovinylene)-2-methoxy-5-(2-ethylhexyloxy)benzene, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(5-aminophenanthroline)europium(III), tris(dinapthoylmethane)mono(phenanthroline)europium(III), tris(biphenoylmethane)mono(phenanthroline)europium(III), bis(dibenzoylmethane)mono(4,7-diphenylphenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dimethyl-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxy-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxyloxy-phenanthroline)europium(III), lithium tetra(8-hydroxyquinolinato)boron; 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, bis(8-hydroxyquinolinato)zinc, bis(2-methyl-8-hydroxyquinolinato)zinc, iridium(III) tris(2-phenylpyridine), tris(8-hydroxyquinoline)aluminum, tris[1-phenyl-3-methyl-4-(2,2-dimethylpropan-1-oyl)-pyrazolin-5-one]-terbium, and mixtures of two or more of any of these.
 51. The method according to claim 35, wherein the light-emitting material is one that is not excited by an alternating current electrical field.
 52. The method according to claim 35, wherein at least two separate light-emitting materials are present, at least one of which is excited by excitation of the electroluminescent phosphor and at least one other of which emits light upon being excited by the excitation of a light-emitting material.
 53. A luminescent device comprising an electroluminescent phosphor in operative contact with a light-emitting material that is selected from the group consisting of poly-(p-phenylenevinylene) (PPV), poly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene] (MEH-BP-PPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene (MEH-CN-PPV), poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-1,2-ethylene-1,4-phenylene] (DiSiPV), polypyridine, poly(p-phenylenevinylene), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene)-alt-co-(4,4′-biphenylene-vinylene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(4,4′-biphenylene)], poly[{9,9-dioctyl-2,7-divinylenefluorenylene}-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene}], poly[{9,9-dioctyl-2,7-bis(2-cyanovinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethyl hexyloxy)-1,4-phenylene}], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylenephenylene)], poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene}-alt-co-{2,5-bis(N,N′-diphenylamino)-1,4-phenylene}], poly[{9-ethyl-3,6-bis(2-cyanovinylene)carbazolylene)}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[(9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di-(p-butylphenyl)-1,4-diaminobenzene], poly[2-(6-cyano-6-methylheptyloxy)-1,4-phenylene), poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-ethylenylbenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], poly[(9,9-dihexylfluorenyl-2,7-divinylenefluorenylene)], poly[(9,9-dihexyl-2,7-(2-cyanodivinylene)-fluorenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly(9,9-dioctylfluorenyl-2,7-diyl, poly(9,9-dihexylfluorenyl-2,7-diyl), poly[9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di(p-butyloxyphenyl)-1,4-diaminobenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-diphenyl)-N,N′-di(p-butyloxy-phenyl)-1,4-diaminobenzene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,10-anthracene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-bis{4-butylphenyl}-benzidine-N,N′-{1,4-diphenylene})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(2-methoxy-5-{2-ethylhexyloxy}-1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9′-spirobifluorene-2,7-diyl], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(2,5-p-xylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(3,5-pyridine)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9-di-{5-pentanyl}-fluorenyl-2′,7′-diyl; poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′{2,2′-bipyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′-{2,2′:6′,2″-terpyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N′bis{p-butylphenyl}-1,4-diaminophenylene)], and mixtures thereof, wherein the electroluminescent phosphor is present in an insulating layer which is located between a first electrode and a second electrode, and wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material.
 54. The device according to claim 53, wherein the first electrode and the second electrode comprise an intrinsically conductive polymer.
 55. The device according to claim 53, wherein the first electrode and the second electrode comprise a substituted or unsubstituted intrinsically conductive polymer that is selected from the group consisting of polyaniline, polyacetylene, poly-p-phenylene, poly-m-phenylene, polyphenylene sulfide, polypyrrole, polythiophene, and polycarbazole.
 56. The device according to claim 53, wherein the light-emitting material is located in the insulating layer.
 57. The device according to claim 53, wherein the electroluminescent phosphor is selected from the group consisting of: CdSe; InAs; LaPO₄, undoped or doped with one or more of Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; ZnS, undoped, or doped with Ag, Cu, Mn, Tb, TbF, or TbF₃; ZnSe; undoped or doped with Mn, or Cu; ZnCdS; M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba, and M^(III)=Al, Ga, In, Y, or is optionally absent, where the compound is undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures thereof.
 58. The device according to claim 53, wherein the electroluminescent phosphor particles are coated with the light-emitting material.
 59. The device according to claim 53, wherein the electroluminescent phosphor particles comprise ZnS:Cu which are coated with poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene].
 60. The device according to claim 53, wherein at least two separate light-emitting materials are present, at least one of which is excited by excitation of the electroluminescent phosphor and at least one other of which emits light upon being excited by the excitation of a light-emitting material.
 61. A luminescent device comprising an electroluminescent phosphor particle that is coated with a light-emitting material wherein excitation of the electroluminescent phosphor by an alternating current electrical field causes the emission of light by the light-emitting material.
 62. The device according to claim 61, wherein the electroluminescent phosphor is present in an insulating layer which is located between a first electrode and a second electrode.
 63. The device according to claim 62, wherein the first electrode and the second electrode comprise an intrinsically conductive polymer.
 64. The device according to claim 63, wherein the first electrode and the second electrode comprise a substituted or unsubstituted intrinsically conductive polymer that is selected from the group consisting of polyaniline, polyacetylene, poly-p-phenylene, poly-m-phenylene, polyphenylene sulfide, polypyrrole, polythiophene, and polycarbazole.
 65. The device according to claim 62, wherein the electroluminescent phosphor can be excited by an alternating current electric field and can emit light at a first wavelength.
 66. The device according to claim 62, wherein the electroluminescent phosphor is selected from the group consisting of: CdSe; InAs; LaPO₄, undoped or doped with one or more of Pr, Nd, Er, or Yb; YOS, undoped or doped with Er; ZnS, undoped, or doped with Ag, Cu, Mn, Tb, TbF, or TbF₃; ZnSe; undoped or doped with Mn, or Cu; ZnCdS; M^(IIA)M₂ ^(III)(S, Se)₄, where M^(IIA)=Ca, Sr or Ba, and M^(III)=Al, Ga, In, Y, or is optionally absent, where the compound is undoped, or doped with Eu²⁺ or Ce³⁺; and mixtures thereof.
 67. The device according to claim 62, wherein the light-emitting material is a material which is excited when in operative contact with the excited electroluminescent phosphor and which is capable of emitting light of a wavelength that is different than the light emitted by the electroluminescent phosphor.
 68. The device according to claim 62, wherein the light-emitting material is selected from the group consisting of: anthracene, undoped or doped with tetracene, aluminum tris(8-hydroxyquinolinate), poly-(p-phenylenevinylene) (PPV), poly[2-methoxy-5-(2′-ethyl)hexoxy-1,4-phenylenevinylene] (MEHPPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-co-4,4′-bisphenylenevinylene] (MEH-BP-PPV), poly[2-methoxy-5-(2′-ethylhexyloxy)-1-(cyanovinylene)phenylene (MEH-CN-PPV), poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-1,2-ethylene-1,4-phenylene] (DiSiPV), Tb tris(acetylacetonate), Eu(1,10-phenanthroline)-tris(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate, Eu tris(dibenzoylmethanato)phenanthroline, Tb tris(acetylacetonate)phenanthroline, Eu(4,7-diphenylphenanthroline)-tris(4,4,4-trifluoro)-1-(2-thienyl)-butane-1,3-dionate, Nd(4,7-diphenylphenanthroline)(dibenzoylmethanato)₃, Eu(dibenzolmethanato)₃-2-(2-pyridyl)benzimidazole, Eu(dibenzolmethanato)₂-1-ethyl-2-(2-pyridyl)benzimidazole, Tb-[3-(5-phenyl-1,3,4-oxadiazol-2-yl)-2,4-pentanedionate]₃, lanthanide-tris(4-methylbenzoate), lanthanide-tris(4-methoxybenzoate), Tb tris(4-methylbenzoate), Tb tris(4-methoxybenzoylbenzoate), Eu tris(4-methoxybenzoylbenzoate), Tb-tris(tetradecylphethalate)phenanthroline, Tb-imidodiphosphinate, Tb 1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one, polypyridine; poly(p-phenylenevinylene), poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene)-alt-co-(4,4′-biphenylenevinylene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(4,4′-biphenylene)], poly[{9,9-dioctyl-2,7-divinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene}], poly[{9,9-dioctyl-2,7-bis(2-cyanovinylene-fluorenylene}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-(1-cyanovinylenephenylene)], poly[{9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene}-alt-co-{2,5-bis(N,N′-diphenylamino)-1,4-phenylene}], poly[{9-ethyl-3,6-bis(2-cyanovinylene)carbazolylene)}-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}], poly[(9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di-(p-butylphenyl)-1,4-diaminobenzene], poly[2-(6-cyano-6-methylheptyloxy)-1,4-phenylene), poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[{9,9-dioctylfluorenyl-2,7-diyl}-co-{1,4-(2,5-dimethoxy)benzene}], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-ethylenylbenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], poly[(9,9-dihexylfluorenyl-2,7-divinylenefluorenylene)], poly[(9,9-dihexyl-2,7-(2-cyanodivinylene)-fluorenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-vinylenephenylene)], poly(9,9-dioctylfluorenyl-2,7-diyl, poly(9,9-dihexylfluorenyl-2,7-diyl), poly[9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N′-diphenyl)-N,N′-di(p-butyloxyphenyl)-1,4-diaminobenzene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-diphenyl)-N,N′-di(p-butyloxy-phenyl)-1,4-diaminobenzene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,10-anthracene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N′-bis{4-butylphenyl}-benzidine-N,N′-{1,4-diphenylene})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(2-methoxy-5-{2-ethylhexyloxy}-1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9′-spirobifluorene-2,7-diyl], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(2,5-p-xylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(3,5-pyridine)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(1,4-phenylene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,9-di-{5-pentanyl}-fluorenyl-2′,7′-diyl; poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′{2,2′-bipyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(6,6′-{2,2′:6′,2″-terpyridine})], poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N′bis{p-butylphenyl}-1,4-diaminophenylene)], 8-hydroxyquinoline, fluorescein, rhodamine, xanthene (substituted or unsubstituted), substituted coumarin, substituted hydroxycoumarin, substituted or unsubstituted tetra-cyanoquinolines, ethidium bromide, propidium iodide, benzoxanthene yellow, bixbenzimide ((2′-[4-hydroxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol), (2′-[4-ethoxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazol)), 4,6-diamidino-2-phenylindole (DAPI), lithium tetra(2-methyl-8-hydroxyquinolinato)boron, bis(8-hydroxyquinolinato)zinc, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(2-phenylpyridine)iridium(III); and tris(8-hydroxyquinolinato)gallium(III), tris(8-hydroxyquinolato)aluminum, tetra(2-methyl-8-hydroxyquinolato)boron, lithium salt, 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, 9,10-di[(9-ethyl-3-carbazoyl)-vinylenyl)]-anthracene, 4,4′-bis(diphenylvinylenyl)-biphenyl, 1,4-bis(9-ethyl-3-carbazovinylene)-2-methoxy-5-(2-ethylhexyloxy)benzene, tris(benzoylacetonato)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(5-aminophenanthroline)europium(III), tris(dinapthoylmethane)mono(phenanthroline)europium(III), tris(biphenoylmethane)mono(phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-diphenylphenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dimethyl-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxy-phenanthroline)europium(III), tris(dibenzoylmethane)mono(4,7-dihydroxyloxy-phenanthroline)europium(III), lithium tetra(8-hydroxyquinolinato)boron; 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl, bis(8-hydroxyquinolinato)zinc, bis(2-methyl-8-hydroxyquinolinato)zinc, iridium(III) tris(2-phenylpyridine), tris(8-hydroxyquinoline)aluminum, tris[1-phenyl-3-methyl-4-(2,2-dimethylpropan-1-oyl)-pyrazolin-5-one]-terbium, and mixtures of two or more of any of these.
 69. The device according to claim 62, wherein the wavelength of light emitted by the light-emitting material is in the range of infrared, visible, or ultraviolet.
 70. The device according to claim 62, wherein at least two separate light-emitting materials are present, at least one of which is excited by excitation of the electroluminescent phosphor and at least one other of which emits light upon being excited by the excitation of a light-emitting material. 